Pre Cast Concrete the Architects Solution Handouts

8/14/2019 Pre Cast Concrete the Architects Solution Handouts

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Precast Concrete: TheArchitects Solution

Outline

Introduction

Manufacturing Process of Precast

Benefits to Architects

Benefits to Owners

Benefits to Contractors

Design and Use

Summary

Introduction

Precast Concrete concrete cast

elsewhere than its final position (ACI)


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Introduction

Architectural Precast - Precast concrete

that will remain visible when in its finalposition, thereby contributing to theaesthetics of the structure or site.

Structural Precast - Precast concrete thatsupports or transfers loads other than itsown weight (e.g. floor & roof loads).

Above Ground Applications

Buildings and structures

Site amenities/accessories

Retaining & sound walls

Bridges

Traffic and security barriers

Road repairs

Fencing

Buildings - Commercial


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Buildings - Residential

Foundations & Walls

Buildings - Residential

Buildings Floor and Roof


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Buildings - Trim

Buildings Modular

Buildings StructuralElements


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Buildings StructuralElements

Site Amenities &Accessories

Site Amenities&Accessories


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SoundWalls

RetainingWalls

Bridges


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Bridges

Traffic Barriers

Security Barriers


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Road Repair

Fencing

Underground Applications

Water and wastewater

Stormwater

Sanitary

Utilities


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Water &

Wastewater

Stormwater

Sanitary


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Utilities

Manufacturing

Forms

Types of Concrete

Materials

Mix Design

Properties

Stripping

Curing

Storage and Shipping

Manufacturing - Forms

Wood most common for architectural,good details, limited number of uses perform

Metal Most common for underground,

durable, reusable for years Fiberglass great detail and finish,

expensive

Formliners resin, elastomeric, plastic,wood, steel, plaster


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Forms - Wood

Forms - Wood

Forms - Metal


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Forms - Metal

Forms

What to watch for:

Forms require drafts and chamfersfor ease of removal

Proper form preparation, seal joints

Proper cleaning and maintenance

Types of Concrete

What is Concrete?

Different types: Conventional wet-cast

Dry-cast

Lightweight

High-performance

Self-Consolidating Concrete (SCC)

Architectural


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Types of Concrete - SCC

Types of Concrete - SCC

Types of Concrete Architectural

Face mix

Minimum thickness after consolidation

one-inch or 1.5 x max. agg. size Similar thermal and shrinkage

coefficients

Similar w/cm ratios and proportions


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Manufacturing - Materials

Coarse and fine aggregate (stone

and sand) 60-70% by volume, 70-85% by mass

Properly Graded

Gap Graded

Note: natural materials will vary

Manufacturing - Materials

Cement

Grey - color may vary

White - more stable for colors

Water - must be potable or meetASTM C 1602

Admixtures

Air

Manufacturing Mix Design

Water-cementitious ratio, lower thebetter (0.40 0.45)

Type IType IType I


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Manufacturing Mix Design

Water-cementitious ratio by volume

300 lbs600 lbs

= 0.504.81 ft3

3.05 ft3

240 lbs600 lbs

= 0.403.85 ft3

3.05 ft3

Hardened Properties

Appearance

Strength

Durability

Moisture penetration

Abrasion resistance

Dimensional stability

Appearance

Precast concrete can be made inmany: Shapes or designs

Colors Textures

Finishes

Combinations of the above

*Repeatable due to quality control


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Strength

Maximum stress concrete can

withstand before failure

Concrete is good in compression,but weak in tension

Durability

A products ability to survive in its

exposure environment for its intended

service life.

Ability to resist internal and external

attack Corrosion of reinforcement

Freeze/Thaw resistance

ASR

Moisture Penetration

Porosity - a ratio of the total voids in amass to the total mass itself

Permeability is a measure of the flowof a liquid or a gas through a substance

Water resistant reduces wetting, butpermits passage of moisture underhydrostatic pressure

Water proof impervious to water ineither liquid or vapor state


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Abrasion Resistance

Ability to resist damage caused by

rubbing Important for:

Floors

Hydraulic Structures

Bridges

Parking Garages

Dimensional Stability

Concrete experiences volumetricchange due to:

Temperature

Moisture

Chemical

External forces

What Effects Concretes

Hardened Properties?

Water-Cementitious ratio

Quality materials and mix design

Good production practices Proper curing procedures

*All of which you get with precast concrete.These are more difficult to ensure in fieldconditions.


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Stripping/Form Removal

Must have appropriate stripping

strength Forms must be removed properly

and completely

Always lift pieces level and asdesigned

Curing

Why cure?

Proper curing temps, procedures

Concrete is the only material thatgains strength over time

Curing affects color

Curing affects strength

Why precast is cured better thanconcrete cast on site


Storage yards

Shipping time

Erection of products


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Storage &Shipping



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Benefits to Architects

Design flexibility Aesthetic versatility

Quality control

Superior strength

Green - sustainability

Readily available

Saves time and money

DesignFlexibility

Concrete can bemade into anyshape that canbe formed

Modular

High level ofdetail

Finishes are ableto simulate

almost anymaterial

Aesthetic VersatilityWide variety of colors


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Aesthetic Versatility

Exposures:None skin, paste only as cast

Light matrix predominant (Acid, AB)

Medium 50/50 matrix and courseaggregate (Acid, AB)

Deep coarse aggregate predominant(AB, EA)

Aesthetic Versatility

Wide variety textures and finishes:

As cast- form finish

Abrasive blast

Acid etched

Exposed aggregate surface retarder

Grinding/tooling

Veneers

Cast stone

Formliners

As-Cast


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Abrasive Blast / Acid Etch

Exposed Aggregate

Exposed Aggregate


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Polished Finish

Veneer

Veneer


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Cast Stone

Formliners

Quality Control

Controlled and monitoredenvironment

Shelter from weather

Consistent quality materials &trained labor

Quality control personnel

Documentation of production foreach piece

Certified plants


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Superior Strength

Precast concrete has superiorstrength over many other claddingmaterials such as:

EIFS, masonry, metals, wood, glass, etc.

Precast concrete can bemultipurpose i.e. used as a primarystructural material, shear walls, etc.

Green and LEED

Precast concrete can relate directly

to four LEED credits and a total ofeight points

Site credit 6 Stormwater management

Site credit 7 Heat Island reduction

Materials & Resources credit 4 Recycled content

Material & Resources credit 5

Regional Materials

Saves Time and Money

Speed of Erection

Rapid enclosure

High level of detail

Able to duplicate almost any material

Excellent to match older materials orexisting architecture


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Benefits to Owner

Durability/extended service life Low maintenance - life cycle costs Fire resistant non combustible - passive

resistance Noise deadening Thermal benefits Security Speed of construction quicker

occupancy Reduced construction costs

Durability/Extended Service Life

100 year service life is possible

Durability/Extended ServiceLife

Low permeability/porosity

High strength

Resistance to storms, hurricanes,UV, rot, mold, pests


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Low Maintenance

No painting No warping

No rusting

No breakage

No moisture infiltration or mold

Reduced joints

Low Maintenance

Fire Resistant

Non-combustible

Reduces insurance

Saves lives

Fire ratings easily achieved


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Noise Deadening

Reduces sound transmission fromboth outside and inside sources

Concrete is a good sound insulator

Thermal Benefits

Reduced air infiltration

Reduced utility costs

Acts as thermal mass

Security

Extremelydifficult to break

into Pest entry no

vermin, termites

Terrorist threats

Hard to steal


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Speed of Construction

Reduce building enclosure time andoverall construction time

Quicker Occupancy = making moneyfaster




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Can reduce overall project costs Precast can be less expensive than

traditional materials

Less site labor reduces costs

Benefits to Contractor

Low site impact

Reduced weather dependency

Speed of enclosure

Saves time and money

Low Site Impact

Site Impact a combination ofstorage space required, site access

and duration of that access,limitations on other trades duringthat access

Precast can be delivered to the siteas needed

Other trades can start sooner


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Low SiteImpact

Reduced Weather Impact

Precast can be erected in all temperaturesand in most conditions

Reduced Weather Impact

Site weather conditions do not effect

the manufacturing process

Rain only helps curing


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Speed of Enclosure

Buildings can be erected and dried-infaster than conventionalconstruction


Precast products can be made whilethe excavation and foundations arebeing performed on site.

Design and Use

Design & cost reduction

Total precast construction

Mock-ups and samples

Colors and finishes

Piece design and componentizing

When not to use precast


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Design and Use Design &Cost Reduction

Start with the overall geometry of thestructure, not the panel

Use repetition Master moldconcept, forms are expensive, allowenough time not to need extra molds

Design and Use Design &Cost Reduction

Big pieces are better then small ones reduce handling and erection time

Multiple finishes can increase cost

Must be constructible

Consider site conditions

Involve precaster early in theprocess initial design phase

Design and Use Total PrecastConstruction


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Design and Use Total PrecastConstruction

Design and Use Total Precast

Construction

Design and Use Mock Ups

Build a full scale mock up of a typicalsection on the site

Build mock ups early in the project View in sun, shade, wet, dry

Use for variation control and acceptance

Establish patching and repair procedures

Evaluate the effects of weathering

May help identify other constructionissues


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Design and Use Colors andFinishes

Visual characteristics are usuallydetermined by the architect

How color is achieved

Recommendations:

Match paste, sand and stone

Use white cement or blends

Use slightly darker matrix with deep exposures

Rounded aggregates help with weathering anduniformity

Design and Use Piece Design& Componentizing

Size & geometry by engineer,precaster

Open and closed piece design

ReturnsClosedOpen

Design and Use Piece Design

& Componentizing

Stress concentrations, handling

Joints and corners


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Design and Use Piece Design& Componentizing

Larger pieces are better Repetition of pieces = reduces costs

Involve the precaster early in the

design process

Consider constructability andshipping

Tolerances

Design and Use

When not to use precast

Mass pours or when monolithic poursare required i.e. dams, nuclear reactors

Slabs on ground

Summary

Precast Concrete: Offers a virtually endless array of colors,

finishes and textures Can allow you to be creative in design

Can reduce construction times, delays andproject costs Is extremely durable 100 year service life Reduces overall life-cycle costs Is produced in a quality controlled

environment Can qualify for LEED credits


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Everybody Wins

with PrecastConcrete!

Thank You!

Pre Cast Concrete the Architects Solution Handouts

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